P111

Introduction H 2 S plays key roles in various physiological processes. So, compounds which can regulate activities of H 2 S producing enzymes are expected to be useful as chemical tools for life sciences and medicine. These compounds also would be able to contribute to the progress of H 2 S research. Here we show the discovery of small molecule inhibitors for 3-mercaptopyruvate sulfurtransferase (3MST) and cystathionine gamma lyase (CSE) by high-throughput screening (HTS). Method For screening, we used a novel fluorescence probe for H 2 S (HSip-1), which has been developed by our group (J. Am. Chem. Soc. 133 (2011) 18003). By using this probe, we established an assay system. In the assay system, the increase of the fluorescence intensity is suppressed, when the enzyme activity is inhibited by a compound and the production of H 2 S decreases. We then performed 3MST and CSE inhibitor screening of a chemical library containing about 160,000 compounds. Results We selected compounds which could suppress the fluorescence increase of HSip-1. After the repeatability test, we excluded HS − reactive compound as false positive compounds, and then found hit compounds. These compounds were selective against targeted H 2 S producing enzymes. Conclusion As a result of screening, we could discover both selective 3MST and CSE inhibitors. We will examine the utility of these compounds by applying them to living cells and we expect these compounds would be used as research tools.